The present invention generally relates to a character graphic information display device which decodes and processes the received character graphic information so as to display it on a display portion.
In recent years, a videotex which is capable of projecting character graphic information such as news, weather forecasts, stock market information and so on composed of characters and figures, onto the picture face of a television image receiving machine for home use using a telephone circuit, and a character multiplex broadcasting arrangement which similarly transmits the character graphic information with broadcasting waves have been put into practical use. Furthermore, recently the character graphic information (rank 3 or rank 5 picture faces) having a higher display density have been provided for services. Although a personal display device having a higher display performance of its display portion including a display device such as CRT or the like is needed in order to display the character graphic information of higher density, it becomes much higher in price. The present inventors thin out the picture elements of the high density picture face so as to convert it into a standard density display, or display only one portion of the high density picture face so as to receive the character graphic information of a higher density with the conventional television image receiving machine, and develop a character graphic information display device.
Such a character graphic information display apparatus as described hereinabove will be described hereinafter with reference to the drawings.
FIG. 1 shows the construction of the conventional character graphic information display device. Referring to FIG. 1, reference numeral 1 is a character graphic information decoding portion for decoding the character graphic information into character graphic picture images; reference numeral 2 is a microprocessor circuit for controlling the character graphic information decoding portion; reference numeral 3 is a receiving circuit for fetching the character graphic information as digital data from the picture image signals; reference numeral 4 is a RAM for storing the received character graphic information, using it as a working region of the microprocessor circuit 2; reference numeral 5 is a ROM for accommodating a program for controlling the microprocessor circuit 2; reference numeral 7 is a display memory for storing the character graphic picture images decoded by the microprocessor circuit 2; reference numeral 6 is a display processing circuit for composing into RGB signals the character graphic picture images stored in the display memory 7; reference numeral 9 is a character generator for using the character graphic information by decoding it into the character graphic picture images, reference numeral 8 is an additional sound decoder for processing the additional sound data to be included in the character graphic information; reference numeral 10 is a keypad for instructing the selection of the character graphic information to the character graphic information decoding portion. Reference numeral 20 is a television signal receiving portion; reference numeral 21 is an antenna; reference numeral 22 is a television signal receiving circuit; reference numeral 23 is an audio demodulation amplifying circuit; reference numeral 24 is a brilliance amplification color demodulating circuit; reference numeral 25 is a picture image audio switching circuit for switching or mixing among the picture image audio signal of the television, the RGB signal to be outputted from the character graphic information decoding portion, and the additional sound signal; reference numeral 26 is an audio amplification outputting circuit; reference numeral 28 is a speaker; reference numeral 27 is a picture image amplification outputting circuit; reference numeral 29 is a display portion for displaying the picture images, where, for example, a cathode-ray tube is used.
The operation of the character graphic information display device of such character as described hereinabove will be described hereinafter.
The television signal received from the antenna 21 is demodulated by a television signal receiving circuit 22 of the television signal receiving portion 20, with the picture image signal and the audio signal being fetched from the output thereof. The picture image signal is inputted into the receiving circuit 3 of the character graphic information decoding portion 1. The receiving circuit 3 fetches the character graphic information from among the picture image signals. A user instructs the microprocessor circuit 2 as to the selection of the desired character graphic information from among all of the character graphic information by the operation of the keypad 10. The microprocessor circuit 2 selects the instructed character graphic information, and stores it in the RAM 4, and also, processes the decoding operation, converts it into the character graphic picture images, stores it in the display memory 7 using the character generator 9 whenever necessary in accordance with the contents of the program stored in the ROM 5. The character graphic picture images stored in the display memory 7 are composed into RGB signals by the display processing circuit 6. Also, the additional sound data to be included in the character graphic signal is converted into the additional sound signal by the additional sound decoder 8.
The audio signal and the picture image signal demodulated by the television receiving circuit 22 are inputted and processed respectively into the audio demodulation amplifying circuit 23, the brilliance amplification . color demodulating circuit 24, and are inputted into a picture image audio switching circuit 25. The picture image audio switching circuit 25 selects the former in the displaying of the character graphic picture image, selects the latter in the displaying of the television picture images by the switching of the picture image signal (RGB signal) and an audio signal (additional sound signal) to be outputted from the character graphic information decoding portion 1, and the picture image signal of the television and the audio signal. The selected audio signal and the picture image signal are respectively inputted into the speaker 28, the display portion 29 respectively through the audio amplification outputting circuit 26 and the picture image amplification outputting circuit 27. By the above described operation, the user may display on the display portion 29 the selected character graphic information.
With respect to such a character graphic information display device, the present inventors have thought of thinning out the picture elements of the high density picture face by the microprocessor circuit 2, when the display density of the received character graphic information is higher, to convert it into the standard density for storing it in the display memory 7. When the picture face with the density being converted into the standard density cannot be made out, the picture face region to be displayed is keyed in to the microprocessor circuit 2 by the operation of the keypad 10. By the storing of the instructed region in the display memory 7, the microprocessor circuit 2 can display only one portion of the high density picture face on the display portion 29.
In a character graphic information display device of such a construction as described hereinabove, the operations of, first, contracting the whole picture face information to display it, then, specifying a display region for expanding, displaying it, and expanding, displaying it are necessary. Furthermore when a different region is desired to be expanded, displayed, it is necessary to once display the whole picture face information, and to specify again the region desired to be expanded, so that the simplicity of the use is desired. Also, if the specification of the expanded region is the same as the high density picture face when the character graphic information is composed of a plurality of standard density picture faces, one standard density picture face has to be specified by a plurality of operations. Although there is a character graphic information with the high density picture face and the standard density picture face being mixed in it, only the high density picture face is expanded in consideration of the easy-to-see high density picture face, thus causing the different feelings with respect to the standard density picture face, with a defect that the picture face is not correctly displayed. When the displaying operation is effected by the expansion of one region portion of the picture face, the character graphic information except for in the display region to be expanded, displayed takes more processing time, because the processing which is the same as the processing for the displaying operation is effected, with a problem that the picture face information in the region desired to be displayed is not displayed immediately.